US4611332A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transferred electric arc
Assignee: SKF Steel Engineering AB
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Filing: 1984-08-14
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Granted: 1986-09-09
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Expires: 2004-08-14
Abstract
Abstract In a method for supplying thermal energy by means of a plasma arc heater to a reactor filled with solid, lump reduction material, the thermal energy is supplied via an outer or transferred arc, one electrode of which is formed by the heater and the other electrode of which is formed by the reduction material in the reactor.
Inventors
- 👤 Sven Santen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 22:25
CPC Classifications
C; C22; C22B; C22B9/00; C22B9/16; C22B9/22; C22B9/226; B; B01; B01J; B01J19/00; B01J19/0006; B01J19/0013; C22B4/00; C22B4/005; H; H05; H05B; H05B7/00; H05H; H05H1/00; H05H1/24; H05H1/48; B01J2219/00; B01J2219/00049; B01J2219/00051; B01J2219/00157; B01J2219/08; B01J2219/0894
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
243 words
A method of chemical reduction in a shaft furnace comprising the steps of: (a) providing a plasma arc heater having at least two cylindrical electrodes in the wall of said furnace such that the plasma gas generated by such heater may be directed into said furnace; (b) continuously maintaining said furnace substantially filled with reduction material; (c) generating a first inner electric arc between two of said at least two cylindrical electrodes; (d) passing a reducing gas through said plasma arc heater thereby to convert said gas to a plasma gas; (e) causing said plasma gas to burn away the reduction material immediately in front of the heater so as to form a reaction cavity in front of the heater; (f) transferring said arc from between said two electrodes such that it is blown into the cavity and thence extends between only one of said electrodes and said reduction material contained in the furnace, said arc being caused to substantially only so extend by providing at least one current conductor in electrical contact with said reduction material, said current conductor permitting the completion of an electric arc between the electrode and the reduction material, said current conductor being located such that substantially no electric arc extends between said electrode and said current conductor; (g) supplying powdered material containing the material to be reduced into said cavity; and (h) reducing said material to be reduced and withdrawing the so reduced material from the reactor.
Claim 2
Independent Claim
243 words
A method of chemical reduction in a shaft furnace comprising the steps of: (a) providing a plasma arc heater having at least two cylindrical electrodes in the wall of said furnace such that the plasma gas generated by such heater may be directed into said furnace; (b) continuously maintaining said furnace substantially filled with reduction material; (c) generating a first inner electric arc between two of said at least two cylindrical electrodes; (d) passing a reducing gas through said plasma arc heater thereby to convert said gas to a plasma gas; (e) causing said plasma gas to burn away the reduction material immediately in front of the heater so as to form a reaction cavity in front of the heater; (f) transferring said arc from between said two electrodes such that it is blown into the cavity and thence extends between only one of said electrodes and said reduction material contained in the furnace, said arc being caused to substantially only so extend by providing at least one current conductor in electrical contact with said reduction material, said current conductor permitting the completion of an electric arc between the electrode and the reduction material, said current conductor being located such that substantially no electric arc extends between said electrode and said current conductor; (g) supplying powdered material containing the material to be reduced into said cavity; and (h) reducing said material to be reduced and withdrawing the so reduced material from the reactor.
Claim 3
Dependent Claim
16 words
A method according to claim 1 wherein the powdered material is fed into the plasma gas.
Claim 4
Dependent Claim
30 words
A method according to claim 1 wherein the powdered material is supplied together with at least one additive material selected from the group consisting of oxygen, water and slag former.
Claim 5
Dependent Claim
19 words
A method according to claim 1 wherein the chemical reduction is the direct reduction of metal oxide to metal.
Claim 6
Dependent Claim
368 words
Apparatus for carrying out an endothermic reaction using a plasma arc heater for the supply of thermal energy to a reactor by use of a reduction gas which is entirely or partially taken through the heater and converted to gas plasma, such apparatus comprising: (a) a reactor in the form of a shaft furnace having upper and lower portions, said reactor adapted to be filled with reduction material in use of the apparatus; (b) a charging top to said reactor; (c) means in said charging top for providing continuous supply of solid, lump reduction material to said reactor and for providing a pressure drop so that hot gases in the reactor do not depart via the top countercurrent to the said supply thereat; (d) a gas outlet in the upper portion of the reactor; (e) outlet means at the bottom of the reactor for metal and slag; (f) a plasma arc heater in the lower portion and in the wall of said reactor positioned such that the plasma gas generated by said heater may be directed into said reactor, said plasma arc heater having at least two cylindrical electrodes positioned such that a first inner electric arc can be generated between two of said at least two cylindrical electrodes; (g) supply means to said plasma arc heater for injecting powdered material and reduction gas into the lower portion of the reactor, said supply means being adapted so as to permit said inner electric arc to be blown into said reactor and thence to be transferred and to extend between only one of said cylindrical electrodes and said reduction material in said reactor; (h) a current source for said plasma arc heater; (i) means connecting said plasma arc heater to said current source; (j) at least one current conductor positioned to be immersed in and in electrical contact with said reduction material having been fed in said charging top, said current conductor being positioned in said reactor such that when the reactor is substantially filled with said reduction material substantially no electric arc extends between said heater and said conductor; and (k) electric circuit means connecting said at least one current conductor to said current source for the heater.
Claim 7
Dependent Claim
368 words
Apparatus for carrying out an endothermic reaction using a plasma arc heater for the supply of thermal energy to a reactor by use of a reduction gas which is entirely or partially taken through the heater and converted to gas plasma, such apparatus comprising: (a) a reactor in the form of a shaft furnace having upper and lower portions, said reactor adapted to be filled with reduction material in use of the apparatus; (b) a charging top to said reactor; (c) means in said charging top for providing continuous supply of solid, lump reduction material to said reactor and for providing a pressure drop so that hot gases in the reactor do not depart via the top countercurrent to the said supply thereat; (d) a gas outlet in the upper portion of the reactor; (e) outlet means at the bottom of the reactor for metal and slag; (f) a plasma arc heater in the lower portion and in the wall of said reactor positioned such that the plasma gas generated by said heater may be directed into said reactor, said plasma arc heater having at least two cylindrical electrodes positioned such that a first inner electric arc can be generated between two of said at least two cylindrical electrodes; (g) supply means to said plasma arc heater for injecting powdered material and reduction gas into the lower portion of the reactor, said supply means being adapted so as to permit said inner electric arc to be blown into said reactor and thence to be transferred and to extend between only one of said cylindrical electrodes and said reduction material in said reactor; (h) a current source for said plasma arc heater; (i) means connecting said plasma arc heater to said current source; (j) at least one current conductor positioned to be immersed in and in electrical contact with said reduction material having been fed in said charging top, said current conductor being positioned in said reactor such that when the reactor is substantially filled with said reduction material substantially no electric arc extends between said heater and said conductor; and (k) electric circuit means connecting said at least one current conductor to said current source for the heater.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-09-08 | 1990-03-10 | 1990-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-08 | 1994-03-10 | 1994-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-08 | 1998-03-10 | 1998-09-09 | $7700.00 | Window Closed / Lapsed |